Nonlinear Dual-Phase-Lag Thermo-Physiological Model for Predicting Heat Transport and Biological Response During Laser-Induced Hyperthermia

Abstract

The focus of this study is the development of a nonlinear dual-phase lag (DPL) comprehensive bioheat transfer model, which attempts to capture the behavior of biological tissues under laser irradiation. The model treats thermal conductivity (the tissue’s ability to conduct heat) and volumetric blood flow as functions of temperature. The model also considers laser irradiation as internal heating, which gives rise to a set of coupled thermal relations. By integrating temperature-dependent thermal conductivity and blood perfusion within a dual-phase-lag framework, the model achieves more accurate and realistic predictions of thermal behavior than conventional linear approaches. An implicit finite difference approach with Newton-Raphson is utilized, which is expected to achieve fast convergence and stability. The temperature dependence of thermal conductivity was implemented, and this influences the redistribution of heat as well as the maximum temperature. The results indicate that nonlinear factors (α, β) and blood perfusion are essential in regulating heat distribution and tissue damage progression, while relaxation durations (τ_q, τ_T) considerably influence thermal wave dynamics. Compared to the linear model, the difference is much more pronounced. The results replicate a multitude of published experimental observations and show the adaptability of the model under a variety of numerical approaches. Therefore, the model provides a strong theoretical basis for future work involving the accuracy and potential risks involved with laser-assisted thermal therapies.